When will Pre-Storm Evacuations become a possibility?

[Mike Johnston]

Just thinking about the recent outbreak over the South, and then watching a TWC story on the Enterprise, AL tornado where high school students spent 1 hour and 45 minutes in shelter before the tornado actually hit.

Also, considering the diminishing benefit of warning lead times much over 20 minutes, as has been discussed on here several times.

One has to wonder....at what point will evacuations become a reasonable pre-caution in advance of tornadic storms? Seems like somewhere between 30-40 minutes of warning lead time would come close to a realistic possibility. Of course, there's a myriad of factors, not the least of which would be traffic congestion of people trying to evacuate from a narrow area in a short period of time. Another factor, of course, would be the accuracy of the warning itself including the false alarm rate.

 

[Skip Talbot]

Interesting topic, Mike. It seems to me like it would be a logistics nightmare trying to evacuate a populated location ahead of a tornado without at least a couple hours of notice. Its going to take several minutes for people to get mobilized, and then the traffic congestion will snarl the main roads to a crawl. In theory you don't have to travel very far even to get out of the way of even the largest tornadoes, but the width of your warning polygon is going to be substantial with a half hour, hour, or longer notice. Ten or tens of miles? If the call to evacuate is made and the traffic jam gets nailed, its going to be far worse than if everyone had taken shelter instead. If the area is lightly populated, or the evacuation is made for those already mobile, with ample lead time and careful planning to avoid traffic congestions and false alarms, it seems like a safest option. People complain now about warnings that don't verify. Imagine the agitation after they evacuate a few times.

 

[Rob H]

We're still talking about on average something like 40-50 tornado deaths a year, as opposed to 10,000 dying from dryer fires, or 300 people from coconuts falling on their heads. When you combine the odds of a supercell forming, that supercell going over your house, that supercell producing a tornado, and that supercell producing a powerful enough tornado to destroy your house and kill the inhabitants - you're looking at an amazingly small chance. Drive by a mall on Black Friday, or by a stadium after a football game gets out. That's the kind of traffic an evacuation system would warrant, and you still have the problem of how to notify all these people because most of them still aren't getting the simple "take shelter" message that is sent out today with warnings. Would longer lead times have saved any of the people that died last year on April 27th? Would it have caused more deaths from people driving around instead of taking shelter?

In my opinion, lowering the FAR and increasing reception rate should be the current priorities for emergency warning programs. Increasing lead time should be at most a distant third.

With that being said, I would still attempt to direct my immediate family out of danger's path if possible.

 

[Joshua Nall]

I don't feel that evacuation ahead of a tornado warned storm will ever be a reasonable precaution. Unless of course, government completely controls everything, and I hope that never happens.The bottom line is, you can't make folks do something they don't want to do without controlling them. Much rather live in a place where people are free to make bad decisions. For me any talk like this always gets down to the heart of the matter and that is freedom... to be ignorant even, if that is what folks want to be. For those who choose to evacuate because they choose to be informed, well then I'm glad there won't be so many on the roads that they will be able to get out of the way. My great grandmother survived the famous Witchita Falls, TX tornado by leaving. My mother still has a piece of funiture that survived from her apartment that was destroyed. I personally tell people to stay informed, I don't have a fancy phone, but I was talking to my brother-in-law a while back about him getting an app for his or whatever is needed to see couplets on storms. He said he didn't want to bother with it. Teach people, then let them be.

 

[Cynthia Van Den Broeke]

This is a good question, but as a number of people have pointed out it tends to be sticky for a few reasons. Here's one more to consider: various forms of apathy after a warning is successfully received (I'm distinguishing "received" and "heeded" here, although one could argue that hearing a warning is not receiving it until the threat has been personalized). I live in yet another of those cities that hasn't had a major event in many a year and the folks I have spoken to about their severe weather awareness have thus far quoted to me another one of those legends about how a tornado won't happen here (something about the city being in a low area?). There also seems to be the "that won't happen to me" issue, which I have commonly seen in more than just severe weather situations (e.g. "I won't ever get in a car accident. I'm too careful"). If evacuation were feasible, how many would ignore the warning and go about their daily business anyway? My burning question on this issue: would the same people ignore an evacuation order? It would be interesting to see if there was a change (in either direction) in the rate of warning response (some kind of response other than some form of apathy) with an evacuation order. I will leave that one to social science.

Oh, and the traffic! I have been in a situation where I have been on the phone with relatives fleeing a large outdoor event. Everyone else got the same idea and left town instead of returning to their hotels or seeking a local shelter. The road was packed and they were probably moving ~15 mph with a potentially tornadic storm bearing down on the column of vehicles. All were very fortunate the tornado developed just east of the city...

 

[Jeff Duda]

I think the cost vs. benefit of evacuating people ahead of tornadoes in all situations except for at large gatherings (outdoor sporting events, state/county fairs, outdoor concerts, etc being the main examples) is pretty bad and would suggest that it's not worth the effort and planning. It would also require an extreme amount of precision in the forecast track of a tornado. How accurate are current warnings for tornado tracks? For warnings with more than 15-20 minutes of lead time, accuracy of better than a few miles is going to become unlikely. Precision will also suffer as path uncertainty increases farther out. To make an evacuation system useful, forecast of tornado path with precision of fractions of miles would be required. Although some could probably predict large, strong, long-lived tornadoes with that kind of precision out to a few minutes nowadays, forecasting past a few minutes for your garden variety tornadoes is probably years away (if even in my lifetime).

 

[Elaine Spencer]

Personally, I don't see this EVER becoming feasible on a large scale (i.e. evacuating cities). It makes sense to evacuate for a hurricane that is only moving at, say, 10 to 15 miles per hour and does not strike until 24 to 48 hours after the warning is issued. It does NOT make sense to evacuate for a tornado moving at 40 to 50 miles per hour that will strike within 30 to 40 minutes.

I would prefer that we concentrate on providing better sheltering in place and putting accessible public shelters within reach (walking distance, or less than a 5 minute drive) of the most vulnerable facilities (mobile home parks, campgrounds, etc.). In some cases, existing facilities such as underground parking garages or tunnels could be used and it wouldn't really be necessary to specially construct a shelter.

 

[Stephen Levine]

Tornadoes are brief fleeting occurrences. The practicality of evacuations for such phenomenon is non-existent. I agree with Elaine.. we have the technology now to make every existing home safe - at least in one room- from tornadoes, hurricanes, etc. In addition, through technology such as monolithic dome homes, underground homes and modifications to existing home construction, we can build new homes designed to keep ourselves and prized possessions safe.
I believe that we need to have regulations in place to protect mobile home residents... a shelter within easy walking distance for each subdivision.

 

[TrumanBoyer]

Build better schools

The school kids are told to crouch against a wall, the injuries and deaths are caused by the wall collapsing on them. Most public schools have a rubber membrane roof that gives marginal lateral support to the walls, the roof gets ripped away, ventilation sheetmetal, wires and conduit, etc fly around shredding everything, and when the wind is stronger-- the walls, essentially anchored only at the ground, get knocked over on the kids. IMO they should be told to crouch next to the wall OPPOSITE the approaching storm (usually East, of course).

Membrane roofs are a PITA for maintenance people, UV dries them out and cracks them, (unless they are sealed every 5 years or so), they constantly leak, need expensive repairs, need replacement every 15-20 yrs, and often collapse in rain and snow storms.

For a little more initial investment the schools could have pent roofs that make the buildings MUCH stronger, and easier, cheaper to maintain.

School buildings should be built to be public storm shelters, and not something to flee from when a storm approaches. (and so should Fire Halls !!!)

Complaints about school buildings always seem to be about leaking roofs anyway, and there are still billions of Economic Recovery and Infrastructure Improvement dollars that have not been spent.

Build stronger buildings to replace all those we lost. Go to the Meetings. Talk to the people who can make it happen. Its your money....